Many large mail sorting operations use multiple sorters to handle the quantity of mail that must be processed during the daily operations. These sorting operations can be captive shops or letter shops that manufacture the mail and then presort the mail before it is delivered to the postal authority such as the United States Postal Service (USPS®). Presort operations is another example of a large sorting operation with multiple machines. Many of these presorting operations process many different jobs from different clients or departments. In many cases, the client data and department data must be tracked by mailpiece and reported. Sorting operations are designed to sort the mailpieces into predefined groups of geographically related delivery points (addresses). The grouping relate to postal processing centers and mail carrier routes. Since the delivery point is associated with a number (e.g. ZIP Code) the groupings will be individual numbers or groups and ranges of numbers. For the USPS, the finest depth of sorting is based on the high order 5 digits of the ZIP Code. The next depth of sorting is based on the high order 3 digits and the lowest depth of sorting is also based on the high order 3 digits, but the range of 3 digit numbers is expanded to cover Automated Area Distribution Centers (AADC). Increasing postage discounts are based on the mailpiece sorting results with the largest discount for 5 digit and the least discount for AADC, provided at least 150 mailpieces are in the group and the ZIP Code was encoded in an approved barcode and printed on the mailpiece.
The sorting operator must create a sort scheme to control the sorter during first pass operations when the mailpieces are first processed. The data associated with each job and mailpiece is collected during first pass and stored for later use in generation of a report. The sort scheme determines which ZIP Codes will be sorted into which sort bins. The first pass sort scheme gives priority to high volume 5 digit groups and 5 digit schemes (ranges of 5 digit numbers that get the same discount when combined). Second priority for sort bin utilization is 3 digit groups or schemes. In numerous cases, sort bins will be assigned large ranges for 3 digit numbers. The mailpieces in these bins will be processed on a second pass, with a different sort scheme, to sort the mailpieces to additional 5 digit groups. The second pass is required because there are far more qualifying 5 digit groups than there are bins on the sorter.
Sorter operators will allocate sort bins for the first pass sort scheme to the highest volume 5 digit groups or schemes based on historical data. The operator has to leave available a sufficient number of bins for second pass mail collection and for special purposes, such as reject bins and undeliverable mail. Since a large sorter may have 100 to 260 sort bins, only a few of the thousands of 5 digit sort groups will be sorted to during first pass. This means that a significant amount of mail will have to be processed on second pass or even a third pass. These subsequent passes add significant processing time that may result in not sorting the mail to the finest depth of sort before the mail must be delivered to the postal authority. Significant extra hours of operation are required for the subsequent passes and significant postal discounts may be lost.
Since the sort groups are not known in advance of first pass sortation, all of the sorters in a given operation will run the same first pass sort scheme. Second pass can not be started until all of first pass is competed and analysis of the first pass data is made to create a second pass sort scheme(s). Having the same second pass sort bin designations on each machine also facilitates second pass operation where mail from individual second pass sort bins, with the same bin sort scheme, can be run on different machines during second pass.
A few sorter operators will have different first pass sort schemes on different sorters and use a NO-COUNT mode to run out of scheme mail from one machine on the other machine during first pass operation. In order to use NO-COUNT mode, the sorter must be stopped and the mode selected before the mail is run. Data from the first time the mail was run, on a different machine, is used for postal authority reports. NO-COUNT mode stops data collection. This mode represents high risk because if the operator does not cancel the mode as required, a large volume of mail may be processed incorrectly. In addition, individual mailpiece tracking, as required for the USPS Intelligent Mail operations, can not be accomplished in a NO-COUNT mode.
Hence, there exists a need for the ability to run different first pass sort schemes on each sorter in a sorting facility without stopping operations for NO-COUNT, without losing mailpiece tracking, or waiting for all first pass sorting to complete before re-running the mail that was not sorted to the finest depth of sorting.